1. Field of the Invention
The invention relates to a press-on device in a printing unit of a printing press, more particularly, having a plate cylinder and a rubber blanket cylinder, including a press-on roller applicable against the plate and being swivelable at a spaced distance therefrom about a swivel axis aligned parallel to the axes of the cylinders.
Such a press-on device has been disclosed in the published German Patent Document DE 42 18 602 A1. The press-on roller described therein is formed of two concentrically telescoped tubes, an inner tube of which serves as a bearing support for an outer tube freely rotatably supported thereon, and is provided at ends thereof with axially sprung journal pins, which engage in lateral guides, so that the conventional press-on roller can be displaced against a rear or trailing printing-plate end by actuating elements, fixedly connected to the printing-press frame, outside of a nip plane between the plate cylinder and the rubber-blanket cylinder, in order to insert the rear or trailing printing-plate end with a bent edge into a clamping slot of a clamping device in the plate cylinder. After the printing plate has been locked-up on the plate cylinder, the press-on roller is moved back on a reverse path into a remote rest position. Further known from this publication is a press-on roller with rings formed of elastic material and held axially spaced from one another, on the circumference of the press-on roller in circumferential grooves, the rings being rotatable due to frictional contact with the outer tube of the press-on roller.
A press-on device of similar kinematic construction and action is described in the Japanese Published Non-Prosecuted Patent Application Sho 63-191636. In this heretofore known device, the press-on roller is movable with respect to its support in a guide about a swivel axis disposed parallel to the cylinder axis, in order to promote swiveling of the printing plate onto the plate cylinder. Provided for this purpose is a pneumatic cylinder, which presses the press-on roller against the plate cylinder when the printing plate is inserted. This device also is withdrawn into a remote rest position after the printing plate has been locked up.
Furthermore, protective devices at dangerous locations of a printing unit of a printing press, particularly finger-protection devices of head-protection devices in front of the nip between the plate cylinder and the rubber blanket cylinder and in front of the printing nip between the rubber-blanket cylinder and the impression cylinder have also become known heretofore.